High-accuracy universal polarimeter measurement of optical activity and birefringence of α-quartz in the presence of multiple reflections

The high-accuracy universal polarimeter (HAUP) method for simultaneous measurement of birefringence and optical activity in crystals is used when multiple reflections at the plate faces cause modulated variation of the optical parameters. We applied the HAUP method to obtain the birefringence and gyration tensors of α-quartz as a function of temperature in the range 25–100 °C at λ=632.8 nm. Results for birefringence Δn= ne-no and nonnull gyration tensor components g11,g22=g11, and g33, with samples cut in different crystallography planes, are consistent with crystal symmetry and in good agreement with other reported values. For example, the temperature coefficient d(Δn)/dt for a cut perpendicular to the optical axis is -1.06× 10-6 (°C)-1,g11=(5.9±0.4)×10-5, and g33=-(10.1±0.2)×10-5 at 24 °C.